Evidence for bandlike dispersion in K6C60(110) films

Using angle resolved photoemission we show that bandlike states in K6C60(110) films at 40 K survive in spite of the strong electron-phonon coupling expected in fullerides that should give rise to polaron formation. The momentum dependence and the total bandwidth of the dispersing bands contributing to the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) features agree quite well with one-electron band structure calculations. While a crude estimation of the dimensionless electron-phonon coupling constant lambda, from the temperature dependence of the LUMO linewidth in photoemission spectra, seems to place K6C60 in an intermediate polaronic regime, the expected strong coupling to K+ modes remains uncertain.